| Drug | structure | preparation | comment |
| A)barbiturates | |||
| phenobarbitone | metabolized as P hydroxylation >inactive anticonvulsant *action of barb : 1-prolongatn of cl channel >hyperpolarization 2-promotion of action of GABA >CNS depression | ||
| Mephobarbitone | |||
| B)Hydantoins | |||
| diiphenyl hydantoin (Phenytoin ,Epanutin) | 5,5-diphenyl hydantoin (imidazoline -2,4- dione) | *assay by dissolving sod salt in water then acidify to ppt the base ,filter ,wash ,dried and weigh *metabolite : P hydroxylation *sod salt is used | |
| Ethotoin | 3-ethyl-5-phenylhydantoin | *mode of action of Ethintoin :1-blocking of Na channels (as local anaeth ,antiarryth ) 2- ! Intracellular Ca (w is stimulant) 3-inhhibit protein syn & neurotransimitter syn 4-exhibit GABA like action (inhibitory) *N.B both barbiturate & Ethontoin > 1st stim then depression | |
| C) Oxazolidine- 2,4 -diones | |||
| Trimethadione | 3,5,5 -trimethyl -2,4 -oxazolidine -dione | * it is of little use due to toxic effect *trimethadione opened (fission) upon ttt e alc alkali even on cold form > N-methyl -a-hydroxy isobutyramide | |
| paramethadione (paradione) | 5-ethyl -3,5-dimethyl -2,4 -oxazolidinedione | prep as Trimethadione starting e methyl ethyl ketone | *effective # electrical seizures not chemically induced *toxicity :1-nephrotoxicity 2-bone marrow depression 3-Aplastic anemia 4-photophobia so monthly urine analysis & blood count should be performed |
| D ) succinimide (more safer class) | |||
| Ethosuximide (Zarontin) | 2-ethyl -2-methyl succinimide | *assayed 1-Kjeldahl method (for organic N) drug + NaoH >heat (dist) >NH3 gas >receive in flask > ass std Hcl or H2so4 , form amm sulfate or chloride , tit xxs acid by NaoH (M.O) 2-add know xxs of alkali std & tit of xxs unreacted alkali # std acid | |
| Phensuximide (Milontin) | N-methyl -2-phenyl succinimide | ||
| Methsuximide (celontin) | chemical name :N,2- dimethyl -2-phenyl succinimide | succinimide mech >potentiation of the inhibitory process of neuron | |
| E) Miscellaneous anticonvulsant drugs | |||
| Primidone (Mysoline) | 5-ethyl -5-phenyl hexahydropyrimidine -4,6-dione | *potent widely used *deoxy analogue of phenobarbitone *metabolism 1-phenyl P hydroxylation (inactive ) 2-mic oxdn to phenobarbitone (active) | |
| Carbamazepine | chemical name :5H-dibenzo [b,f] azepine-5- carboxamide *less toxic equal in potency to phenobarbitone & phenytoin *mech :inhibit Na & K conductance & ! Transmission in reticular activating system | ||
| Valproic acid (Depahine) | 2-propyl pentanoic acid | *mode of action by elevating brain level of the inhibitory transmittor GABA | |
| Acetozolamide | *mech :1- it is carbonic anhydrase inhibitor (CAI) in brain cause Co2 accum in the brain & spinal cord 2-+ GABA in brain *disadv :tolerance so used only as adjuvant | ||
| benzodiazepines | |||